Unidirectional current-carrying device



June 4, 1929. D. a: ACKERLY UNIDIRECTIONAL CURRENT CARRYING DEVICE Filed Feb. 11, 1925 Patented June 4, 1929.

{UNITED STATES PA ENT OFFICE.

DONALD e. ACKERLY, or w-ILKINsBuRe, riiNNsYLvANIA, ASSIGNOR 'ro ran-Union SWITCH & SIGNAL COMPANY,

OF PENNSYLVANIA.

OF SWISSVALE, PENNSYLVANIA, A CORPQRATION UNIDIRECT IONAL CURRENT-CARRYING DEVICE.

Application filed February In the-accompanying drawing, Fig.1 is

a View showing, in front elevation, one form of uni-directional current carrying device embodying my invention. Fig-2 is a sectional view along the line IIII of Fig. 1. Fig. 3 is an exploded sectional view illustrating a modified form of the device shown in; Figs. 1 and 2 and also embodying my invention. Fig. 4. is a View, showing in front elevation, another modification of the device shown in thepreceding views and also embodying my invention. Fig. 5 is a scctional view along the line VV of Fig. 4.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Figs. 1 and 2, the device comprises a disk C having asymmetric current carrying characterics, that is, a disk which offers greater reslstance to current flowing through the disk in one direction than to current flowing through the disk inthe other direction. Oneform of disk possessing this characteristic comprises a sheet 2 of metal with a layer 1 of a compound of the metal formed directly thereon. For example the sheet 2 may be copper and the layer 1 cuprous oxide, or the sheet 2'maybeiron and the layer 1 beiron oxide.

In devices of this type, the resistance of-\ .fered by the disk to currents flowing from the oxide to the metal is considerably less with a sleeve 5 of insulating'material.

than the resistance offered to currents flowing in the opposite direction.

I have discovered that devices of the type described give best results when the disk C is subjected to comparatively high pressure, and I have further discovered that for'best results the high pressure applied to the disk 3 should be uniformly distributed over the isk.

In order to subject the disk to such uni. formly distributed high pressure, the device may be constructed as follows. The disk C is provided with a centrally located hole to accommodate the shank of a bolt A. The shank of this' bolt is provided Carv ried also by bolt'A, and located one on each 11, 1925. Serial No. 8,594.

side of disk C are two contact plates B and D of rigid material such as steel. Interposed between the oxide coating 1 of disk 0 and one contact plate B is a malleable washer 4, which I prefer to make of several plies of lead foil or tin foil. This washer covers substantially the entire-face of disk C. Thethreaded end of bolt A is provid-' material are placed under the head of bolt I A and nut 8, respectively. Electrical connections may be made to the device through i wires'lO and 11 attached to plates B and D, respectively.

With the device constructed as thus far described, when nut 8 is turned up to exert high pressure on the disk, the natural resiliency of plates B and D, causes the outer edges of theseplates to spring slightly apart,

thereby resulting in a considerably smaller pressure upon disk C adjacent its periphery than adjacent its center. I

To overcome this conditioInI provide, between disk C and plate D, a shim 3 of annular form and comprisinga single thickness of leadfoil ortin foil. This shim is located in concentric relation with respect to bolt A and is of such size that-the shim is spaced a considerable distance from the bolt in a radial direction as best seen in Fig. 2.

t will therefore be plain that when nut 8 is drawn up, pressure is at first applied to the disk only through shim 3, adjacent the.

edge of thedisk. s the pressure exerted adjacent the center of plates B and D- is increased, the edges of the plates are sprung sli htly apart, thereby permitting plate; D to bear against disk C adjacent the center of the disk. The parts are so proportioned 1 that when the desired pressure is applied to f disk C, the outward springing of disks B and D is compensated for by the shim 3, so. that the pressure is then evenly distributed over the entire area of the disk.

.In the modification shown in Fig. 3', the- "parts are the sameas' in Figs. 1 and 2, ex-

cept that shim 3 is replaced by a pressure washer 3 having a concave face 9 adjacent plate D. The parts are so proportioned that u when the nut 8 is drawnup .toexert the optimum pressure upon disk C, the resiliency of the plates B and D is exactly compensated for by the concave washer 3", and the pressurg on disk C is therefore evenly distribute In the form shown in Fi s. 4 and 5, a flat washer 3 similar to was er 4 is interposed between plate D anddisk' C. The

1 edges of plates B and D are extended be yond the limits of thedisk C, and the tend ency pf thse plates to spring apart when nut 8 is drawn up on bolt A,'is overcome by clamping together the overhanging edges of the contact plates'B and D" by'means of bolts A. With this arrangement of apparatus the plates B and D are maintained'in parallel relation, and the pressure exerted upon disk 0 is evenly distributed. The" claims without departing and scope of m invention. I 7

Having thus escribed my invention, what I claim is:

from the. spirit 1. A- uni-directional current carrying device comprising a disk having asymmetric current carrying characteristics, a contact plate, a bolt passin through said plate and disk, a nut threade on said bolt forclamping'said-plate and disk together under comparatively high pressure, and a shim interposedjbetween said plateand said disk for:

uniformly distributing the pressure exerted by said nut. 7

2. In combination, a bolt, a disk on said 'bolt and having asymmetric current carry- -1ng characterlstlcs WlllCh vary. in response to the pressure applied to the disk, a flat plate on said bolt, a pressure washer-having a concave surface interposed .between said plate bolt to clamps'aid washer' a ainst said disk whereby thedisk is subjecte to a uniformly distributed pressure.

DONALD e. AOKEBLY.

and said disk, and a nut threaded on said I In testimony whereofI afii'x my signature. I 

